U.S. Pat. No. 4,146,926 issued Mar. 27, 1979 to Michel CLERGET et al. discloses an apparatus comprising means for illuminating and over-illuminating a quasi-pinpoint region at the surface of a body, and means for taking views of said quasi-pinpoint region from several stations so as to produce corresponding images, the positions of which are determined relative to respective reference systems in order to derive therefrom the position in space of the quasi-pinpoint region. The position of the illuminated or over-illuminated point may be varied for obtaining information on the shape of the object examined.